Sweating on the legs at night may be caused by kidney yang deficiency (lack of yang energy in the kidneys), yin deficiency and internal heat. 1. Kidney Yang Deficiency: Sweating on the legs at night caused by Kidney Yang Deficiency, accompanied by lumbar and knee soreness (lumbar and knee soreness and weakness), cold pain, or male impotence, premature ejaculation, women’s uterine cold and infertility, loss of libido, or prolonged ejaculation of stools, undigested food in the stools, diarrhea and abdominal pain before dawn, pale or dark, cold, limbs are not warm and other symptoms. 2. Yin deficiency and internal heat: Yin deficiency and internal heat caused by night sweating in bed on the legs, accompanied by flushed cheeks, dry throat, five heart heat (two palms and two feet of the heart of the heat, and self-consciousness of the heart and chest heat), hot flashes (a burst of fever), night sweats (after falling asleep sweating abnormally, waking up sweating to stop), and so on. If the symptoms of night sweating in the legs during sleep do not ease for a long time or are accompanied by other discomforts, consult a doctor in time to find out the cause and carry out targeted treatment.